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iOS Enumerations and Optionals in Swift Introduction to Enumerations Enum Methods

Jonatan Witoszek
Jonatan Witoszek
15,384 Points
Posted by Jonatan Witoszek
Jonatan Witoszek
15,384 Points

Use of unresolved identifier - compilation error

When I try to submit the code I get ¨use of unresolved identifier¨ compilatior error. What can be the cause of this?

Error log:

swift_lint.swift:52:55: error: use of unresolved identifier 'UIBarButtonStyle'
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.done, target: nil, action: nil)
                                                      ^~~~~~~~~~~~~~~~
swift_lint.swift:22:6: note: did you mean 'UIBarButtonItemStyle'?
enum UIBarButtonItemStyle : Int {
     ^
swift_lint.swift:27:7: note: did you mean 'UIBarButtonItem'?
class UIBarButtonItem {
      ^
swift_lint.swift:54:55: error: use of unresolved identifier 'UIBarButtonStyle'
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.plain, target: nil, action: nil)
                                                      ^~~~~~~~~~~~~~~~
swift_lint.swift:22:6: note: did you mean 'UIBarButtonItemStyle'?
enum UIBarButtonItemStyle : Int {
     ^
swift_lint.swift:27:7: note: did you mean 'UIBarButtonItem'?
class UIBarButtonItem {
      ^
buttons.swift 
// Example of UIBarButtonItem instance
// let someButton = UIBarButtonItem(title: "A Title", style: .plain, target: nil, action: nil)

enum BarButton {
    case done(title: String)
    case edit(title: String)

    func button() -> UIBarButtonItem {
      switch self {
        case .done(let title):
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.done, target: nil, action: nil)
        case .edit(let title):
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.plain, target: nil, action: nil)
      }
    }
}

let done = BarButton.done(title: "Save")
let button = done.button()

1 Answer

Steve Hunter
Steve Hunter
57,712 Points

Hi Jonatan,

For the style just pass in .done or .plain without the preceding UIBarButtonStyle; like this:

    func button() -> UIBarButtonItem {
      switch self {
        case .done(let title):
          return UIBarButtonItem(title: title, style: .done, target: nil, action: nil)
        case .edit(let title):
          return UIBarButtonItem(title: title, style: .plain, target: nil, action: nil)
      }
    }

That should work fine.

Steve.